Each new growing season brings its own unique set of circumstances that determine which pests and diseases will be evident in our gardens. This year I am seeing a lot of fire blight in fruit trees and cotoneaster hedges. This virus is devastating to plants it attacks. As bees travel from flower to flower during the blooming season, they can move the virus, and the blossom is an open door for the disease to move into the vascular system of the host plant.
At some point the disease will lodge in the cambium layer of the stem and will girdle that branch. Because the sap stops flowing beyond that point, the leaves suddenly wilt and dry up, giving the appearance of being singed by fire, and thus the name fire blight. The percent of damage determines the chance of survival. If just a few branches are infected, prune them back to healthy wood. The diseased bark will have a sunken appearance so it is usually apparent where the damage starts. It is absolutely necessary to sterilize your cutting tool with a 10-percent bleach solution so you do not transfer the virus from cut to cut. After removing the infected branches I recommend a spray application of Agri-strep. Spray late in the evening so the chemical is absorbed by the leaves rather than evaporating.
This is also the time to prevent squash bug damage to squash and pumpkin vines. The bug lays its eggs at the base of the stem; the larva hatch and bore into the stem where they continue to feed and move farther up the vine, causing the vine to wilt and slowly die. I read about using dill at the base of the plants to deter the damage … I’m giving it a try, but still will use a preventative spray.
I am also seeing tomato blight. The symptoms are lower leaves beginning to turn yellow and developing black spots. Remove those leaves immediately and dispose of them away from the garden. A thorough spray of Maneb or Daconil will prevent the disease from spreading. The disease will spread rapidly because at this point in summer, the plants have often grown dense, so older leaves in the interior of the plant stay wet and give the blight spores an ideal environment to attack. Our high humidity produces dew beginning at dusk and remaining until midmorning, creating perfect conditions for blight. Not controlling the blight will result in total loss of foliage and eventual death of the plant.
Ok, I’ve given you the bad news … the good news is that we don’t have to haul water or drag hoses around to keep the gardens growing and looking good. My gardens are looking excellent and the vegetable garden is rewarding us with wonderful produce and for that I am grateful!